AIM: To examine the actual competencies of public health nurses (PHNs) working in public organizations in Japan in order to clarify the relationship between the level of competency and the number of years of experience and the place of work. METHODS: The subjects were 1799 full-time PHNs working at 135 prefectural public health centers and 115 municipal health centers, which were randomly selected. Each subject received a questionnaire in the mail, requesting basic personal information and a self-evaluation of six levels of achievement in 11 topics in five categories of competencies. RESULTS: The number of respondents was 1261 (70.1%), with a total of 1184 valid responses (65.8%). In terms of the level of competency, the average score was >3 for all items and the number of PHNs who achieved Ladders 5 and 6 was low, with very few achieving Ladder 6, despite having more years of experience. Furthermore, the level of achievement depended on the workplace, position, and academic background. CONCLUSION: The tasks regarding the education of PHNs in Japan are to establish achievement goals clearly and incrementally and to develop methods and systems that consistently and systematically increase competencies, not only in basic undergraduate education, but also for employed PHNs, through specialized education. In particular, educational methods that lead to high-quality experiences need to be selected in order to develop competencies.